The correct answer is A. achieve.
The word “insurmountable” means “too great or difficult to be overcome.” The word “tall” means “of great height.” The word “trivial” means “of little importance or value.”
In the sentence “The obstacles seem to be insurmountable, but no one should doubt what this fearless woman can accomplish,” the word “insurmountable” is used to describe the obstacles that the woman is facing. The sentence is saying that the obstacles are very difficult to overcome, but the woman is fearless and determined, and no one should doubt that she will be able to accomplish her goals.
The word “tall” could be used to describe the obstacles, but it would not be the best word to use. The word “tall” does not convey the sense of difficulty or challenge that the word “insurmountable” does.
The word “trivial” could not be used to describe the obstacles. The word “trivial” means “of little importance or value.” The obstacles that the woman is facing are not trivial; they are very important to her, and she is determined to overcome them.